Blind Ultrasound Sweeps Using Low-Cost Portable Device Can Identify High-Risk Pregnancies

By MedImaging International staff writers
Posted on 19 Jul 2023

Image: Obstetric volume sweep imaging shows significant promise in diagnosing pregnancy complications (Photo courtesy of Freepik)

Ultrasound technology has seen extensive growth and expansion in diagnosis and management applications. Its increasing affordability, durability, and portability have improved global access, including in some low- and middle-income countries (LMICs), where it's frequently used in obstetrics among other applications. However, widespread availability and routine use of ultrasound in the majority of LMICs remain limited due to obstacles such as lack of education, training, trained personnel, and ultrasound equipment. A recent study, however, has found that untrained operators performing blind ultrasound sweeps with an affordable, portable, battery-powered device demonstrated high sensitivity and specificity for detecting high-risk pregnancy complications.

Researchers at The Johns Hopkins University School of Medicine (Baltimore, MD, USA) have proposed a solution to eliminate barriers to widespread ultrasonography: volume sweep imaging with a portable, low-cost ultrasound system, supplemented by telemedicine for remote interpretation by a trained specialist or artificial intelligence. This strategy involves blind sweeps of the ultrasound probe, guided by external anatomic landmarks to direct transducer movements. It can be performed by operators without prior medical knowledge, requiring only brief training.

The single-center, prospective cohort study involved 168 women in their second and third trimesters from October 2020 to January 2022. Non-specialists, without previous formal ultrasound training, were briefly trained on a simple eight-step approach to perform a limited obstetric ultrasound examination using blind sweeps of a portable ultrasound probe using external landmarks. Five blinded maternal-fetal medicine subspecialists interpreted these blind sweeps. The primary outcome was the identification of pregnancy complications, such as fetal malpresentation, multiple gestations, placenta previa, and abnormal amniotic fluid volume.

A total of 194 blinded ultrasound examinations were conducted, resulting in 1,552 blinded sweep cine clips. Trainees performed 49 ultrasonograms with normal results and 145 ultrasonograms with abnormal pregnancy results with known complications. The sensitivity for detecting a pre-specified complication was 91.7% among women with abnormal results, with the highest detection rates of 100% for multiple gestations and 91.8% for noncephalic presentation. High negative predictive values of 96.1% for placenta previa and 89.5% for abnormal amniotic fluid volume were also observed. Furthermore, researchers noted a substantial to perfect mean agreement, ranging from 87% to 99.6%, for these pregnancy complication outcomes.

“Closing the gap of the significant health care disparities in obstetrics will require new and innovative strategies,” stated the researchers. “Obstetric volume sweep imaging shows significant promise as a tool to diagnose pregnancy complications and merits further investigation and development.”